Arin and Kaidos
Zones are always locked in time and space. But Zones like the black castle, in which the original owners have already made provisions are even different.
The spirit in such Zones where the original owners gave power to oversee it has absolute power in it. They draw power directly from the influx of mana– the time-space that made zone a thing.
To remove the hold of the spirit and temper with their power, all you need to do is split apart time and space and create an outside interference. And the easiest way to do that is to open a portal directly to the outside.
Now, the amount of power needed to open a portal like that from inside an unclaimed zone is astonishing. In an Iron zone, you need to be at least Gold. Or use a gold artifact.